Systems and methods for synthetic jet enhanced natural cooling

ABSTRACT

A method and system for increasing cooling of an enclosure is provided. The component enclosure includes one or more sidewalls defining a volume, the sidewalls are configured to substantially surround a heat generating component positioned within the volume. The component enclosure further includes a synthetic jet assembly positioned adjacent at least one of the sidewalls. The synthetic jet assembly includes at least one synthetic jet ejector having a jet port. The jet port is aligned at least one of perpendicularly, parallelly, and obliquely with a surface of the at least one sidewall. The synthetic jet assembly is configured to direct a jet of fluid through the port at least one of substantially parallel to the surface, perpendicularly onto the surface, and obliquely toward the surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

Notice: More than one reissue application has been filed for the reissueof U.S. Pat. No. 7,990,705. The reissue applications are U.S.application Ser. No. 13/956,904 (the present reissue application), whichis a reissue application of U.S. Pat. No. 7,990,705; U.S. applicationSer. No. 14/593,087, which is a divisional reissue application of U.S.application Ser. No. 13/956,904; and U.S. application Ser. Nos.15/070,427 and 15/070,483, which are divisional reissue applications ofU.S. application Ser. No. 14/593,087.

BACKGROUND OF THE INVENTION

This invention relates generally to component enclosures and, moreparticularly, to systems and methods for enhancing natural convectioncooling of component enclosures.

In at least some known application areas, it is important for componentsand systems to be light weight and reliable, for example, systems,including the various digital and power electronics systems that providecomputational power and electrical power to an aircraft. Passive coolingof components is known to be reliable. However, passive cooling is alsothe least effective cooling method from a cooling performance point ofview, typically resulting in a larger system for a given amount ofcooling. Some options that are used to extend the capability of passivecooling include extended surfaces and new material with higher thermalconductivity. Extended surfaces increase the heat transfer area.Extended surfaces include fins, ribs, and other protrusions. Materialswith higher thermal conductivity decrease the thermal resistance of theenclosure. Both extended surfaces and new higher thermal conductivitymaterial achieve higher performance without affecting the simplicity andreliability of natural convection. However, they have performancelimitations.

When the loss density extends that where passive cooling is practical,then active gas or liquid cooling is employed. Active gas or liquidcooling may result in a lighter, but less reliable system. Whenimprovements made using extended surfaces and advanced materials reachtheir limit, active cooling, using a fan or other gas cooling device,can be used wherein a cooling gas is forced across and/or against thesurface, reducing the fluid film thermal resistance substantiallycompared to natural convection. In addition to taking cooling airavailable from the immediate vicinity, the cooling gas in a forcedconvection approach could be conditioned, making it colder, and thusmore effective. A further option is liquid cooling. Liquids, typicallyare a more effective heat transfer fluid than gas, and thus can removemore heat. Active gas cooling and liquid cooling are less reliable andmore complex than a passive cooling system and they both require systemswith moving parts which are inherently less reliable than a passivecooling approach.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a component enclosure includes one or more sidewallsdefining a volume, the sidewalls are configured to substantiallysurround a heat generating component positioned within the volume. Thecomponent enclosure further includes a synthetic jet assembly positionedadjacent at least one of the sidewalls. The synthetic jet assemblyincludes at least one synthetic jet ejector having a jet port. The jetport is aligned at least one of perpendicularly, parallelly, andobliquely with a surface of the at least one sidewall. The synthetic jetassembly is configured to direct a jet of fluid through the port atleast one of substantially parallel to the surface, perpendicularly ontothe surface, and obliquely toward the surface.

In another embodiment, method of increasing cooling of an enclosureincludes positioning a synthetic jet assembly adjacent at least one of aplurality of sidewalls of the enclosure wherein the synthetic jetassembly includes at least one synthetic jet ejector having a jet port.The jet port is aligned at least one of perpendicularly, parallelly, andobliquely with a surface of the at least one sidewall and the syntheticjet assembly is configured to direct a jet of fluid through the jet portat least one of substantially parallel to the surface, perpendicularlyonto the surface, and obliquely toward the surface.

In yet another embodiment, an electronic component system includes acomponent enclosure including a plurality of sidewalls defining avolume, a heat generating component positioned within the volume, and asynthetic jet assembly positioned adjacent at least one of the pluralityof sidewalls. The synthetic jet assembly includes at least one syntheticjet ejector having a jet port. The jet port is aligned at least one ofperpendicularly, parallelly, and obliquely with a surface of the atleast one sidewall. The synthetic jet assembly is configured to direct ajet of fluid through the jet port at least one of substantially parallelto said surface, perpendicularly onto said surface, and obliquely towardsaid surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-6 show exemplary embodiments of the method and systems describedherein.

FIG. 1 is a perspective view of a known natural draft cooled componentenclosure;

FIG. 2 is a heat profile map of the enclosure shown in

FIG. 1;

FIG. 3 is a component enclosure in accordance with an exemplaryembodiment of the present invention;

FIG. 4 is a heat profile map of the enclosure shown in

FIG. 3;

FIG. 5A is a cross-sectional view of the synthetic jet assembly shown inFIG. 3 in accordance with an exemplary embodiment of the presentinvention during a compression or expulsion phase.

FIG. 5B is a cross-sectional view of the synthetic jet assembly shown inFIG. 3 during an expansion or ingestion phase;

FIG. 6 is a cross-sectional view of a synthetic jet assembly inaccordance with another exemplary embodiment of the present invention;and

FIG. 7 is an exploded cross-sectional view of the synthetic jet assemblyshown in FIG. 3 in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates embodiments of theinvention by way of example and not by way of limitation. It iscontemplated that the invention has general application to enhancingcooling and disrupting laminar flow in industrial, commercial, andresidential applications.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

FIG. 1 is a perspective view of a known natural draft cooled componentenclosure 100. Enclosure 100 includes a plurality of sidewalls 102 and atop wall 104 forming an enclosed volume in which heat generatingcomponents (not shown) may be located. Air surrounding enclosure 100removes heat a surface 106 of sidewalls 102 typically by convection. Airnear a lower portion 108 of sidewall 102 receives heat generated bycomponents in enclosure 100 and passed through sidewall 102 byconduction. The warmed air rises adjacent to sidewall 102 formingstreams 110 of air rising due to natural convection. As the air risesadjacent to sidewall 102 the air tends to receive more heat from upperportions 112 of sidewall 102. As the air receives more heat, itstemperature increases and its ability to receive more heat diminishes,thereby reducing its effectiveness as a cooling media for enclosure 100.A total amount of heat that can be removed from enclosure 100 definesthe amount of heat that may be generated by the heat-generatingcomponents without causing a failure of the components. Because the heatremoval capability of natural circulation cooling is limited, otherheat-removal methods are often employed as either the primary coolingmethod or at least as a supplemental cooling method. For example, someknown component enclosures include water-cooling, fans, and/or forcedair cooling.

FIG. 2 is a heat profile map 200 of enclosure 100 (shown in FIG. 1). Map200 includes an x-axis 202 representing a position along the height ofsidewall 102 (shown in FIG. 1). A y-axis 204 represents a distanceextending away from sidewall 102. A first temperature gradation 206illustrates a first temperature away from enclosure 200 and proximatelower portion 108. A second temperature gradation 208 illustrates alaminar layer of air flow that includes a greater amount of heat thangradation 206. A third temperature gradation 210 illustrates a laminarlayer of air flow that includes a greater amount of heat than gradation208. A fourth temperature gradation 212 illustrates a laminar layer ofair flow that includes a greater amount of heat than gradation 210.Gradation 212 is at a higher temperature than gradations 206, 208, and210 and the higher temperature reduces the cooling effectiveness ofgradation 212.

FIG. 3 is a component enclosure 300 in accordance with an exemplaryembodiment of the present invention. In the exemplary embodiment,enclosure 300 includes one or more sidewalls 302 defining a volume (notshown) configured to substantially surround a heat generating component(not shown) positioned within the internal volume. Enclosure 300includes a synthetic jet assembly 304 positioned adjacent at least oneof sidewalls 302. Synthetic jet assembly 304 includes at least one jetport 306 extending through a housing 308. In the exemplary embodiment,jet port 306 is aligned substantially perpendicularly with respect torespective sidewall 302 such that a jet of fluid is ejectorsubstantially parallel to respective sidewall 302. In other embodimentsjet port 306 may be aligned parallelly and obliquely with respect tosidewall 302 such that jet port 306 directs a jet of fluidperpendicularly towards sidewall 302 or obliquely towards sidewall 302respectively.

In the exemplary embodiment, enclosure 300 includes at least onesidewall 302 that includes an extended surface, such as a rib, a fin, orother protrusion from the surface of sidewall 302 that tends to increasethe surface area of sidewall 302 that is in contact with ambient airoutside of enclosure 300. When sidewall 302 includes an extendedsurface, jet port 306 may be aligned parallelly, perpendicularly, orobliquely with a surface of the extended surface.

Housing 308 may be a separate device that is couplable to enclosure 300,for example, as a retrofit addition to enclosure 300 or as a separateaddition to enclosure 300 during an initial assembly of enclosure 300.In other alternative embodiments, synthetic jet assembly housing 308 isformed integrally with a surface of sidewall 302.

Housing 308 may also include a plurality of jet ports 306 to accommodatea synthetic jet assembly 304 having multiple synthetic jet ejectors (notshown in FIG. 3) in a single housing 308. Additionally, housing 308 mayinclude a plurality of jet ports 306 to accommodate multiple syntheticjet assemblies 304 in a single housing 308. In an embodiment of thepresent invention, multiple synthetic jet ejectors may be coupledtogether in serial flow communication in a single synthetic jet assembly304. Such an arrangement provides an additional pressure increase topropel the jet exiting jet port 306 a greater distance and/or in a morecoherent formation for a greater distance than a single synthetic jetejector in a synthetic jet assembly 304.

FIG. 4 is a heat profile map 400 of enclosure 300 (shown in FIG. 3). Map400 includes an x-axis 402 representing a position along the height ofsidewall 302 (shown in FIG. 3). A y-axis 404 represents a distanceextending away from sidewall 302. Synthetic jet assembly 304 isconfigured to direct a jet of fluid substantially parallel to sidewall302. The jet of fluid disrupts the laminar flow of fluid along a surfaceof sidewall 302, permitting the jet to provide additionally cooling airto the surface of sidewall 302 and permitting ambient air to reach thesurface of sidewall 302 cooling sidewall 302 further.

FIG. 5A is a cross-sectional view of synthetic jet assembly 304 inaccordance with an exemplary embodiment of the present invention duringa compression or expulsion phase. FIG. 5B is a cross-sectional view ofsynthetic jet assembly 304 during an expansion or ingestion phase. Inthe exemplary embodiment, synthetic jet assembly 304 includes housing308 and at least one synthetic jet ejector 502. Synthetic jet ejector502 includes a jet port 306 that may be oriented perpendicularly,parallelly, or obliquely with a surface 504 of a component 506 to becooled. Synthetic jet assembly 304 is configured to direct a flow offluid 508 through jet port 306 that exits jet port 306 as a jet of fluid510 that is parallel to the surface, perpendicular to the surface, oroblique toward the surface. Synthetic jet ejector 502 includes apiezoelectric actuator 514. Actuator 514 is configured to vibrate underthe influence of a piezoelectric effect such that jet of fluid 510 isgenerated and exits jet port 306. Jet of fluid 510 may be configuredsuch that vortex rings 516 are formed in jet of fluid 510. Vortex rings516 aid in disrupting the laminar film that may form along a naturalconvective flow cooled surface. Although described as working with agaseous media, synthetic jet assembly 304 is also able to utilize adielectric fluid as the working fluid.

A small amount of electrical power is drawn by piezoelectric actuator514 causing piezoelectric actuator 514 to vibrate. During a first phaseof operation of synthetic jet ejector 502, shown in FIG. 5A,piezoelectric actuator 514 compresses inwardly towards cavity 518expelling the fluid out of cavity 518 through jet port 306. During asecond phase of operation of synthetic jet ejector 502, shown in FIG.5B, piezoelectric actuator 514 expands outwardly away from cavity 518drawing the fluid into cavity 518 through jet port 306. Piezoelectricactuator 514 is designed into synthetic jet ejector 502 such that thegeometry permits the vibrating action to draw fluid through jet port 306and into a cavity 518 and then subsequently expel the fluid out ofcavity 518, again through jet port 306. The physics of suction andexpulsion through jet port 306 are different. When a fluid is drawnthrough jet port 306, it draws the fluid from an area all around theorifice. Thus, most of the fluid volume is from fluid in the areaimmediately around jet port 306. When synthetic jet ejector 502 expelsthe fluid out of jet port 306, a jet is formed. The jet travels at ahigh velocity and remains intact for a substantial distance away fromjet port 306.

The jet can be directed in a various ways. The jet can be directedperpendicularly to a surface. Such direction tends to provide additionallocal cooling to the area of the surface towards which, the jet isdirected. If the jet is directed parallel to a surface, the jet not onlyprovides direct cooling to the surface by increased fluid velocity alongthe surface, but it also entrains additional fluid along the peripheryof the jet. Thus the amount of fluid that participates in enhancing thefluid along the surface is not only that which is expelled fromsynthetic jet cavity 518, but additional fluid that is entrained by thejet.

FIG. 6 is a cross-sectional view of a synthetic jet assembly 600 inaccordance with another exemplary embodiment of the present invention.In the exemplary embodiment, housing 308 includes a plurality ofsynthetic jet ejectors 502 oriented in serial flow communication suchthat a flow from a first synthetic jet ejector 602 discharges into asecond synthetic jet ejector 604 which in turn discharges into a thirdsynthetic jet ejector 606. The flow generated in first synthetic jetejector 602 is configured to be in phase with the flow being generatedin second synthetic jet ejector 604, into which first synthetic jetejector 602 discharges and second synthetic jet ejector 604 isconfigured to be in phase with the flow being generated in thirdsynthetic jet ejector 606, into which second synthetic jet ejector 604discharges. By controlling the voltage applied to each piezoelectricmember associated with first synthetic jet ejector 602, second syntheticjet ejector 604, and third synthetic jet ejector 606, the flow of fluidthrough synthetic jet assembly 600 can be facilitated being increased inflow and/or pressure permitting an enhanced jet to be formed.

FIG. 7 is an exploded cross-sectional view of synthetic jet assembly 304in accordance with an embodiment of the present invention. In theexemplary embodiment, synthetic jet assembly 304 includes a top cover702, a first spacer ring 704, a first piezoelectric actuator 706, asecond spacer ring 708, a second piezoelectric actuator 710, a thirdspacer ring 712, and a bottom cover 714 all stacked in a sequentialadjacent relationship. One or more alignment tabs 716 provide for anaxial alignment of the aforementioned components and to provide forcoupling the components together using respective pin connectors 718. Agroove 720 inscribed in an inner face of top cover 702 and bottom cover714 is configured to receive an o-ring (not shown) for sealing thecavity formed between top cover 702 and first piezoelectric actuator 706and between second piezoelectric actuator 710 and bottom cover 714. Agap 722, 724, and 726 in respective spacers 704, 708, and 712 providesingress and egress of fluid into and out of the cavities duringoperation.

The above-described embodiments of a method and system of applyingsynthetic jets to the surface cooling of electronic boxes provides acost-effective and reliable means for enhancing natural circulationcooling of component enclosures. More specifically, the methods andsystems described herein facilitate disrupting a laminar flow layeralong a surface of the enclosure. In addition, the above-describedmethods and systems facilitate directly supplying additional coolingmedia to the enclosure and entraining additional fluid to provide anincreased flow. As a result, the methods and systems described hereinfacilitate enhancing cooling of components without significant addedweight and/or reliability costs in a cost-effective and reliable manner.

While the disclosure has been described in terms of various specificembodiments, it will be recognized that the disclosure can be practicedwith modification within the spirit and scope of the claims.

What is claimed is:
 1. A component enclosure comprising: one or moresidewalls defining a volume configured to substantially surround a heatgenerating component positioned within said volume; and a synthetic jetassembly positioned adjacent and is formed integrally with a surface ofat least one of the sidewalls and external to said volume, saidsynthetic jet assembly including at least one synthetic jet ejectorcomprising a jet port, said jet port aligned at least one ofperpendicularly, parallelly, and obliquely with a surface of said atleast one sidewall, said synthetic jet assembly is configured to directa jet of fluid through said port at least one of substantially parallelto said surface, perpendicularly onto said surface, and obliquely towardsaid surface, such that the jet of fluid flows external to said volume.2. An enclosure in accordance with claim 1 3 wherein said synthetic jetassembly comprises a plurality of jet ports.
 3. An enclosure inaccordance with claim 1 A component enclosure comprising: one or moresidewalls defining a volume configured to substantially surround a heatgenerating component positioned within said volume: and a synthetic jetassembly positioned adjacent and is formed integrally with a surface ofat least one of the sidewalls and external to said volume, saidsynthetic jet assembly including at least one synthetic jet ejectorcomprising a jet port, said jet port aligned at least one ofperpendicularly, parallelly, and obliquely with a surface of said atleast one sidewall, said synthetic jet assembly is configured to directa jet of fluid through said port at least one of substantially parallelto said surface, perpendicularly onto said surface, and obliquely towardsaid surface, such that the jet of fluid flows external to said volume:wherein said synthetic jet assembly comprises a plurality of syntheticjet ejectors enclosed in a single housing.
 4. An enclosure in accordancewith claim 3 wherein said synthetic jet assembly comprises a pluralityof synthetic jet ejectors coupled together in serial flow communication.5. An enclosure in accordance with claim 1 3 wherein said synthetic jetejector comprises ejectors each comprise a piezoelectric actuator, saidactuator configured to vibrate such that a flow of fluid is generated.6. An enclosure in accordance with claim 1 3 wherein at least one ofsaid plurality of sidewalls comprises an extended surface, said jet portaligned at least one of perpendicularly and obliquely with a surface ofsaid extended surface.
 7. A method of increasing cooling of anenclosure, said method comprising coupling a synthetic jet assembly toan external surface of at least one of a plurality of sidewalls of theenclosure, the synthetic jet assembly including at least one syntheticjet ejector including a jet port, the jet port being aligned at leastone of perpendicularly, parallelly, and obliquely with a surface of theat least one sidewall, the synthetic jet assembly being configured todirect a jet of fluid through the jet port at least one of substantiallyparallel to the surface, perpendicularly onto the surface, and obliquelytoward the surface, such that the jet of fluid flows external to theenclosure.
 8. A method in accordance with claim 7 9 wherein coupling asynthetic jet assembly comprises coupling a synthetic jet assemblyhaving a plurality of jet ports.
 9. A method in accordance with claim 7A method of increasing cooling of an enclosure, said method comprisingcoupling a synthetic jet assembly to an external surface of at least oneof a plurality of sidewalls of the enclosure, the synthetic jet assemblyincluding at least one synthetic jet ejector including a jet port, thejet port being aligned at least one of perpendicularly, parallelly, andobliquely with a surface of the at least one sidewall, the synthetic jetassembly being configured to direct a jet of fluid through the jet portat least one of substantially parallel to the surface, perpendicularlyonto the surface, and obliquely toward the surface, such that the jet offluid flows external to the enclosure; wherein coupling a synthetic jetassembly comprises coupling a synthetic jet assembly having a pluralityof synthetic jet ejectors enclosed in a single housing.
 10. A method inaccordance with claim 7 A method of increasing cooling of an enclosure,said method comprising coupling a synthetic jet assembly to an externalsurface of at least one of a plurality of sidewalls of the enclosure,the synthetic jet assembly including at least one synthetic jet ejectorincluding a jet port, the jet port being aligned at least one ofperpendicularly, parallelly, and obliquely with a surface of the atleast one sidewall, the synthetic jet assembly being configured todirect a jet of fluid through the jet port at least one of substantiallyparallel to the surface, perpendicularly onto the surface, and obliquelytoward the surface, such that the jet of fluid flows external to theenclosure; wherein coupling a synthetic jet assembly comprises couplinga synthetic jet assembly having a plurality of synthetic jet ejectorscoupled together in serial flow communication.
 11. A method inaccordance with claim 7 9 wherein said synthetic jet ejector comprisesejectors each comprise a piezoelectric actuator, the actuator configuredto vibrate.
 12. A method in accordance with claim 7 A method ofincreasing cooling of an enclosure, said method comprising coupling asynthetic jet assembly to an external surface of at least one of aplurality of sidewalls of the enclosure, the synthetic jet assemblyincluding at least one synthetic jet ejector including a jet port, thejet port being aligned at least one of perpendicularly, parallelly, andobliquely with a surface of the at least one sidewall, the synthetic jetassembly being configured to direct a jet of fluid through the jet portat least one of substantially parallel to the surface, perpendicularlyonto the surface, and obliquely toward the surface, such that the jet offluid flows external to the enclosure; wherein at least one of saidplurality of sidewalls comprises an extended surface and whereincoupling a synthetic jet assembly comprises aligning the jet port atleast one of perpendicularly and obliquely with a surface of theextended surface.
 13. An electronic component system comprising: acomponent enclosure comprising a plurality of sidewalls defining avolume; a heat generating component positioned within the volume; and asynthetic jet assembly comprising a housing formed integrally with andpositioned adjacent an external surface of at least one of the pluralityof sidewalls, said synthetic jet assembly including at least onesynthetic jet ejector comprising a jet port, said jet port aligned atleast one of perpendicularly, parallelly, and obliquely with a surfaceof said at least one sidewall, said synthetic jet assembly is configuredto direct a jet of fluid through said port at least one of substantiallyparallel to said surface, perpendicularly onto said surface, andobliquely toward said surface, such that the jet of fluid flows externalto the volume.
 14. An enclosure in accordance with claim 13 15 whereinsaid synthetic jet assembly comprises a plurality of jet ports.
 15. Anenclosure in accordance with claim 13 An electronic component systemcomprising: a component enclosure comprising a plurality of sidewallsdefining a volume; a heat generating component positioned within thevolume; and a synthetic jet assembly comprising a housing formedintegrally with and positioned adjacent an external surface of at leastone of the plurality of sidewalls, said synthetic jet assembly includingat least one synthetic jet ejector comprising a jet port, said jet portaligned at least one of perpendicularly, parallelly, and obliquely witha surface of said at least one sidewall, said synthetic jet assembly isconfigured to direct a jet of fluid through said port at least one ofsubstantially parallel to said surface, perpendicularly onto saidsurface, and obliquely toward said surface, such that the jet of fluidflows external to the volume; wherein said synthetic jet assemblycomprises a plurality of synthetic jet ejectors enclosed in a singlehousing.
 16. An enclosure in accordance with claim 17 wherein thesynthetic jet assembly comprises a plurality of jet ports.
 17. Acomponent enclosure comprising: a synthetic jet assembly coupled to anexternal surface of at least one of a plurality of sidewalls of theenclosure, the synthetic jet assembly including at least one syntheticjet ejector including a jet port, the jet port being aligned at leastone of perpendicularly, parallelly, and obliquely with a surface of theat least one sidewall, the synthetic jet assembly being configured todirect a jet of fluid through the jet port at least one of substantiallyparallel to the surface, perpendicularly onto the surface, and obliquelytoward the surface, such that the jet of fluid flows external to theenclosure; wherein the synthetic jet assembly comprises a plurality ofsynthetic jet ejectors enclosed in a single housing.
 18. A componentenclosure comprising: a synthetic jet assembly coupled to an externalsurface of at least one of a plurality of sidewalls of the enclosure,the synthetic jet assembly including at least one synthetic jet ejectorincluding a jet port, the jet port being aligned at least one ofperpendicularly, parallelly, and obliquely with a surface of the atleast one sidewall, the synthetic jet assembly being configured todirect a jet of fluid through the jet port at least one of substantiallyparallel to the surface, perpendicularly onto the surface, and obliquelytoward the surface, such that the jet of fluid flows external to theenclosure; wherein the synthetic jet assembly comprises a plurality ofsynthetic jet ejectors coupled together in serial flow communication.19. An enclosure in accordance with claim 17 wherein the synthetic jetejectors each comprise a piezoelectric actuator, the actuator configuredto vibrate.
 20. A component enclosure comprising: a synthetic jetassembly coupled to an external surface of at least one of a pluralityof sidewalls of the enclosure, the synthetic jet assembly including atleast one synthetic jet ejector including a jet port, the jet port beingaligned at least one of perpendicularly, parallelly, and obliquely witha surface of the at least one sidewall, the synthetic jet assembly beingconfigured to direct a jet of fluid through the jet port at least one ofsubstantially parallel to the surface, perpendicularly onto the surface,and obliquely toward the surface, such that the jet of fluid flowsexternal to the enclosure; wherein at least one of the plurality ofsidewalls comprises an extended surface; and wherein the jet port isaligned at least one of perpendicularly and obliquely with a surface ofthe extended surface.